code: def start(self):
      self._init_timer()
      self.started = True
      if self.global_step_count >= self.start_step:
          get_accelerator().synchronize()
          self.start_time = time.time()
  
imports: import time
  from numpy import mean
  from deepspeed.utils.logging import log_dist
  from deepspeed.accelerator import get_accelerator
label_desc: Use image node_id 4 for calling the ThroughputTimer obj's underlying member method code with example usage: obj.start() without return types